Healthy plum crumble

Name: Healthy plum crumble
Ingredients: 200g/7oz jumbo rolled oats; 2 tbsp runny honey; Pinch salt; 2 tsp oil (such as sunflower, corn, rapeseed or light olive oil); ½ tsp ground cinnamon; 1kg/2lb 4oz ripe plums, halved and stoned (if desired although not essential); 50g/1¾oz golden caster sugar; 2 star anise; 1 medium orange, zest and juice